Optical appliance.



No. 756,958. PATENTED APR.12, 1904.

v r J. HARRAES.

OPTICAL APELIANGE. APPLIOATION FILED Nov. as, 1903. no MODEL. a sums-sum1.

No. 756,958. PATENTBD APR. 12, 1904.: J. HARRABS. OPTICAL APPLIANCE.

APPLIUATION FILED NOV. 23, 1903.

3 sums-sum: 2.

' no MODEL.

IPATENTED APR. 12., 1904.

J. HARRAES.

OPTICAL APPLIANCE.

APPLICATION FILED NOV. 23, 1903.

3 SHEBTS-SHEET 3.

N0 MODEL.

Elllllllllllllllllllllllh fweizfir f Ja'hmmmw UNITED STATES PatentedApril 12, 1904.

PATENT OFFICE.

OPTICAL APPLIANCE.

SPECIFICATION forming part of Letters Patent No. 756,958, dated April12, 1904:. Application filed November 23, 1903. Serial No- 182,330. (Nomodel.)

To all whom it may concern:

Be it known that I, J OHANN HARRAES, a citizen of the United States,residing in the city of Chicago, county of Cook, and State of Illinois,have invented a new and useful Improvement in Optical Appliances, ofwhich the following is a specification.

My invention relates to optical appliances for testing human vision; andthe general objects of the invention are, first, to provide a simple anddurably constructed appliance which may combine in itself the means formaking a considerable number of tests each of which usually requires oneor more instruments or appliances; second, to provide means whereby themaking of the tests becomes greatly simplified, thereby minimizing theprobability of error either from an improper adjustment of the applianceor mistake on the part of the operator in reading the indicia; third, toso combine the tests that one may assist in the making of another,thereby reducing the amount of time and effort required; fourth, toeliminate the necessity for numerical calculation upon the part of theoperator, and, fifth, to provide means whereby the operator may make aseries of tests rapidly, so that one test may follow another before themuscles of accommodation of the eye of the patient may change thecondition of the eye. By this means one test serves as a check upon theother and the liability of an erroneous prescription is greatlylessened.

More specific objects of the invention are concerned with the diflerentcontrivances and details of construction, which will be described morefully hereinafter, and pointed out in the accompanying claims.

I attain these objects by the mechanism shown in the accompanyingdrawings, in which 7 Figure l is a perspective view of the device, takenfrom a point in front thereof. Fig; 2 is a rear view of the main screen,showing the lens-disk, disk-plate, and axis-indicator in positionthereon. Fig. 3 is similar to Fig. 2, except that the dial-plate andaxis-indicator are'removed to thereby better exhibit the method ofmounting the lens-disk. Fig. 4 is a vertical central sectional View ofthe ed of metal.

screen and adjacent parts. Fig. 5 is a rear view of the screen, showingthe cylinder-bar mounted in position thereon. Fig. 6 1s a detail viewillustrating the method of mounting the cylinders in the cylinder-bar.Fig. 7 is a sectional view taken on the line 7 7 Fig. 6. Fig. Sis adetail view, in vertical section, taken transversely to the cylinder-barand showing the method of slidingly mounting said cylinder-bar in itsholder. Fig. 9 is a face view of the cylinder-bar drawn to a decreasedscale. Fig. 10 is a perspective view of the axis-indicator, and Fig. 11is a transverse sectional view thereof.

Similar numerals denote similar parts throughout the several views.

The screen 1 is mounted on the rod 2 and is preferably circular inoutline and construct- In order to providefor vertical adjustment andalso a rotary movement about avertical axis, said rod is telescopicallymounted in the stand 3, said stand being provided with a clamp 4,whereby said rod may be rigidly held in anydesired position. The clamp5, formed at the bottom of said stand, enables the appliance to be fixedto a desk or table at the edge thereof in such position as to bestaccommodate both oculist and patient.

Preferably at the center of screen 1 is the aperture 6, at the front ofwhich is fixed the eyepiece 7. The head-rest 8 is mounted upon thescreen, above said eyepiece, and is adapted to make contact with the topof theforehead of the patient to thereby control the vertical as Well asthe horizontal location of the eye of the patient and maintain the eyesteady in front of the aperture 6. The advantage of my headrest over thechin-rests commonly employed is that the jaw of the patient is free tomove to answer the questions of the practitioner without producing amovement of the head and eye of the patient. In order to accommodate theappliance to different patients, the shank 9 of the head-rest 8 isslotted to receive the set-screw 10, whereby said head-rest is adjustably secured to the screenl.

The lens-disk 11 is pivotally secured to the back of the screen 1 by thepin 12 or other suitable means and is provided with a series of lenses13 13 of different strengths. The

lenses are arranged to form a circle near the periphery of disk 11, sothat when the disk is rotated different ones of the lenses 13 will bebrought opposite to the aperture in the eyepiece 7 1n order that anyparticular lens 13 may remain stationary in the line of vision behindthe eyepiece 7 a spring-actuated click or pawl 14 is pivoted to screen 1in such position as to yieldingly engage the notched periphery of saiddisk 11, as best shown in Fig. 3.

It is common in making eye tests to employ a test card or chart at whichthe patient is required to look and by the aid of which the patient andpractitioner may determine what prescription is necessary. WVhen suchcard or chart is placed at a distance from the patientas, for example,upon the opposite side of the room in which the test is being madea roomof considerable size is necessary. I avoid the necessity for a largeroom by reducing the size of the characters upon the chart in properproportion and bringing such chart near to the eye of the patient.Suitable means for accomplishing this are shown in Figs. 1 and 1 andelsewhere in the drawings, wherein such charts are mounted upon a holder15, which in the present instance is cubical in form. Said chart-holderis secured to the arm 16, said arm being secured to the screen 1,preferably by means of the socket 17, removably supported upon the stud18 in said screen. In order that said socket 17 may be readily removed,I prefer to form a clamp 19 at the rear extremity thereof, said clampbeing controlled by the screw 20. By tightening the screw 20 the clamp19 may be caused to grip said stud 18 and hold said socket 17 and arm'16in position.

The above-described parts are suflicient for making complete tests todetermine the error of refraction in the eye of a patient, which erroris usually referred to as deficiency of vision. The lenses 13 are allnumbered as to their strength, and in order to decide as to the strengthof lens necessary to correct the deficiency of vision it is merelynecessary to rotate the lens-disk 11 and bring to a point opposite theeyepiece 7 such one of the lenses 13 as produces the greatest efiiciencyof vision. In order to readily determine the strength of the particularlens opposite to the eyepiece 7 at any given moment, a series of numbers21 is arranged in a circle upon the lens-disk 11, so as to pass in frontof the fixed pointer 22, formed on the fixed dial-plate 23. The partsare so arranged that the strength of the lens in line with the eyepiecewill correspond to the number adjacent to said pointer 22.

The dial-plate 23 above mentioned is rigidly secured to the back of thescreen 1 by means of screws or in any other suitable manner, and saiddial is graduated upon its rear face to indicate the angle ofinclination of the normal axis of the eye of the patient. The holder 24is rigidly fixed to and extends rearwardly from the dial-plate 23 andserves to support the axis-indicator 25. In the preferred form saidholder 2 1 is cylindrical and provided with a slot 26 for receiving thedisk-like body of said axis-indicator. Said slot is of substan tiallythe same width as the body of the axisindicator, so as to preventvibration or play in a fore-and-aft direction, and said slot extends toor below the center of the'holder, so that the indicator may be removedby simply lifting it from the holder. The sides of the holder remainingbelow slot 26 serve to sustain the axis-indicator 25 and keep the centerthereof coincident ,with the line of sight through eyepiece 7. Thesimplicity of construction and ease with which the axis-indicator may beplaced in mm or removed constitutes one of the advantageous features ofmy appliance. The said axis-indicator contains a double prism 27 at itscenter, and the parts are so arranged that said indicator may berevolved within the holder 24 without removing said prism from a centralposition in front of the aperture in the eyepiece 7 The rotation of saidaxis-indicator varies the incliriation of the normal axis of the prism27,

and the angle of inclination is measured by means of a pointer 28, whichtravels across the face of the dial-plate 23 when said axisindicator isrotated in its holder 24:. For convenience ahandle 29 is provided on thepointer of said axis-indicator, whereby said indicator may be rotated.

When it is desired to make a test of the eye to determine the normalaxis thereof, it is merely necessary with this appliance to rotate thepointer 28 to the left or right of the vertical position and read thedial-marking at which said pointer 28 is adjacent when the best visionof the patient has been determined. This is determined in practice bynoting the apparent relative positions of a disk marked upon thetest-chart employed.

For determining the axes or meridians of greatest and least efliciencyin cases of astigmatism my appliance is also provided with a bar 30,containing a number (preferably twelve) of cylinders 31 of difierentconvexities and concavities. Said bar is mounted so as to slide in adirection transverse to the line of .vision through the eyepiece 7 Adesirable manner of mounting said bar is afforded by the holder 32,which is adapted to support and guide said bar in its travel in front ofsaid eyepiece. The socket 33 at the bottom of said holder is constructedto fit over the post 34: on the bar 16 for removably retainingsaidholder in position. The cylinders 31 are mounted in such a manner thateach is independently revoluble in said bar 30. To accomplish this end,the said bar 30 is apertured to receive the circular cylinder-holders35. Said holders have a circumferential groove 36 in their peripheryadapted to receive the key 37 in the manner best shown in Figs. 6 and 7.Said key consists of a rod, screw, bolt, rivet, or similar devicecontained in bar in position to pass through said groove 36, and therebyrevolubly retain said holders in position in said bar. For the purposeof rotating said holders 35 and also indicating at what angle a lens maybe lying said holders are provided with pointers 38, and the differentangles of inclination are marked in a circle upon bar 30 adjacent to therim of the holders 35 in the manner shown in Fig. 6. In testing with thecylinders 31 the holder 32 is placed in position behind the screen 1 andthe bar 30 inserted in said holder. The practitioner then ascertains bytrial what angle of inclination of a cylinder gives the best resultswith the patient. When this angle is ascertained, the practitionerrotates every one of the cylinders 31 to such angle of inclination inbar 30; Subsequently the practitioner slides the bar 30 in the holder soas to bring different ones of the cylinders 31 into the line of sightthrough aperture 6 to thereby determine which of said cylinders producesthe best vision in the patient, As it is merely necessary to slide thebar 30 in its holder 32 in order to bring a different cylinder into theline of sight, it is evident that the diflerent cylinders may be broughtinto line very rapidly one after the other, and, moreover, inasmuch aseach cylinder is independently revoluble in bar 30 the test may be madeWith the cylinders at any angle without changing the angle ofinclination of said bar. By preference the cylinders in 31 are arrangedin bar 30in the order of their conveXity or concavity, and usually thetest for angularity will be made by means of the weakest one of saidcylinders;

I do not wish to be understood as limiting myself to the preciseconstruction or arrangement of parts here shown, for these may beconsiderably varied without departing from the spirit of my invention.

What Iclaim as new, and desire to secure by Letters Patent, is

1. In an optical appliance, the combination with the supporting parts,of a slidable member, a set of cylinders; a set of holders for saidcylinders revolubly mounted side by side in said slidable member, saidholders being circular in form and having a circumferential groove intheir peripheries; and akey in said slidable member for entering thegroove in said holders for the purpose described.

2. In an optical appliance, the combination with the supporting parts,of a slidable member, a cylinder, a circular cylinder-holder revolublymounted in said slidable member; a pointer on said holder and markingson said slidable member adjacent to the periphery of said holder forindicating the angles of inclination of said pointer.

3. In an optical appliance, the combination of a screen havingasight-aperture therein; a lens-disk behind said screen and a head--restadjustably mounted upon said screen above the sight-aperture therein,said head-rest being adapted to make contact with thetop of the foreheadof the patient to thereby control the vertical as well as the horizontallocation of the eye of the patient substantially in the manner and forthe purpose described.

J OHANN HARRAES.

Witnesses:

HOWARD lVL'CoX, J. I. MCDONALD.

